C14-Earth's resources Flashcards
What are finite resources
resources that will run out ,if we continue to exploit them , cannot be replaced as quickly as they are being used .
Examples of finite resources
Crude oil , limestone , metal ores . coal
WHat are renweable resources
RESORUCES THAT CAN BE REPLACED AS QUICKL AS WE USE THEM ,
Examples of renewable resources
wool , rubber , water
Meaning of Sustainable
using a resource responsibly so that it meets the needs of current generations , but in a way that it will not effetc future generations .
What can we do to reduce the strain of natural resources ?
Use synthetic materials
Why are synthetic matrials better than natural resorces , what is one porblem iwth syntthtic maetials
They last longer and peform better over long periods of time .
They cost more and are harder to make than naterial materials .
How are natural mateirals and synthetics materials that come from the same raw materialds different ?
Synthetic mateirls are chmeiclaly modified befor ebing used .
Why should estimations of resources running out only be expressed int erms of orser of magnitudes ?
The predictions do not take into account the recycling of resources which will be significant in the future.Or how much the future will use , are more altenrtives found ?
What are two things Earth’s natural resources do for us ? (Give examples for each )
Provide us with energy (crude oil , fossil fuels )
Provide us with resources (rocks, (building ) , metals
What are Finite resources ? (Give examples )
Resources that will run out if we continue to use them (e,g fossil fuels )
What are renewable resources ? (Give examples )
Resources that can be replaced as we use them (crops and biofuels )
What are sustainable resources ?(Give examples )
Meeting the requirements of human needs
Draw the water cycle
See chemistry book
What is pure water
Only contains water and nothing else , no dissovled substances .
What is potable water
Safe to drink , can contain dissolved substances
What is the first step for making water from a reservoir potable ?
Water is passed through a special fitler made of fine sand and gravel , this removes any remaining particles or grit so the water is clean .
What is the second step for making water from a reservoir potable ?
Water enters the water tretment works , passes through a screen with metal bars close together , to catch large objects such as twigs or leaves .
What is the third step for making water from a reservoir potable ?
Goes through a settlement tank , where sand and soil settle out . Aluminium sulfate and lime are added to the water , so smapp particles of dirrt clump togeteher and sink to the botom of eater .
What is the fourtht step for making water from a reservoir potable ?
A small amount of chlorine is added to the wter to killa ny bacteria in the water .
What is the last step for making water from a reservoir potable ?
The ph of the water is checked and corrected so it is neutral , then stored in large tanks and reservoirs to be pumped out where needed
Three ways to kill microorganisms in water ?
Chlorine , ozone can be added , or a uv light could be used
How can you test the water is pure >
You can test the boiling point of the water so it is 100degrees
Name another process that can be used instead of distialltion ?
Reverse osmosis
define desalination
Desalination is just removing slalt from water .
A disadvanatge of distillatio
Distillation reuqires large amount of energy to boil the water , making ot expensive
How does reverse osmosis work ?
Reverse osmosis uses membranes to separate dissolved salts from salty water .
Disadvanatge of reverse osmosis
Reverse osmosis uses energy to makehigh pressures neeeded , making it expensive .
Why should bottled water in a supermkret not be described as pure water ?
As pure water does not contain dissolved substances ,whereas bottled water is potable water which does contain dissolved substances .
How is copper obtainued usually ?
extracting the copper metal .
Smelting - copper ore is heted to a high temperture in a furnace with air to produce impure copper .
Disadvantages of smelting
Smelting and prufiying copper ore uses a larg amount og elerctiricty and energy
Costs a lot and wil cause pollution to the enivornment .
Why do we have to look for other altenratives than we usually use to extract copper ? What do we have to do ?
Copper ores are becoming scares so we have to extract copper from low grade ores
What is a low - grade ore ? Whats are the disadvanatges
of extracitng copper this way
A low grade orce contains a small amount of copepr , so it is harder to extract the copper economically from these ores /
What are the two methods to extract copper from low grade ores ?
Bioleaching and phytomining
What is a disadvaatge of bioleaching ?
It is a slow process .
How does bioleaching work
Bacteria is mixed with the low grade ore
The bacteria carry out chemical reactions and produce a solution called leachate
The leachate contains the mtal compound we want .
How does phytoming work ?
Plants are gorwn on land containing the metal compounds that we want
The plats absorb the metal compound and concentrate it in their tissue
the plants are then harvested and burned
in the end the ash contains a relatively high conecntration of the metal compond we want .
What do we do after phytoming and bioleaching ?
To extract the metal form the compound ,
we can displace the copper by using iron (as iron is more reactive than copper )
Or electrolysi
What is electrolysis ?
breaking down a substance containing ions using electricity .
ADVANTAGES OF PHYTOMINING ANF BIO-LEACHING
both processes allow us to economically extract metals from low grade ores (important as copper is scarce )
These methods do not involve digging transport and disposing of large amount of rock unlike traditional mining .
when copper is purified by electrolysis , which electrode does the pure copper collect at , explain (2marks)
Metal ions are alawyas positivley chatged , therefore in eelctrolysis they are alaways attracted to and deposited in the negative electrode .
In Phytoming , how can the metal be extracted from the metal compound
Copper ions can be leached from the ash by adding sulfuric acid .
OR displacng the copper using scrap irona dnd then electrolysis .
How can copepr be extracted in bioleaching
u can displace the copper using scrap iron and then use electrolysis .
What does LCA stand for ?
Life cycle assesments
What is LCA
It is an attempt to put a number on the enviromental impacts of a product
Stages of LCA production
add outputs too
Extracting raw materials - huge amount of energy reuqried
Manufacture - eneergy needed to transport product
Production
Use / reuse
recylce / waste management - energy needed to transport products .
Examples of outputs of LCAS
energy disspiated to the surroudnign
atmospheric emissions
waterbone wastes
Plastic or paper bag ? (6 marks)
see notesfor answer
Whats wrong with LCAS ?
Caannot always measutr how damaging this are to the enironment so have to make estimates / valued judgement not always accurate .
LCAS can be biased - to support their claims by advertisers
They only highligh the enivronmental impacts of a product not its cost or perfomrance levels .
Why should LCAS be coarried out on new products ?
to assess the environmental impact of the products, process or services.
PLASTIC BAG
RAW MATERIALS
Crude oil is a finite resource; fractional distillation, cracking and polymerisation all require a lot of energy.
MANUFACTURE
Cheaper to make large quantities of bags from plastic.
USE
Lower impact on the environment because plastic bags are usually stronger so they can be reused many times.
DISPOSAL
Can sometimes be collected and recycled; if disposed of as litter, they do not biodegrade; in landfill, may take decades or centuries to degrade.
PAPER BAG
RAW MATERIALS
Can be made from recycled paper, or from trees. Making paper from trees requires more energy than recycling paper, but much less than making plastics.
MANUFACUTRE
More expensive to make bags from paper because the handles must be glued on.
USE
Relatively short lifetime; can only be reused a limited number of times.
DISPOSAL
Can be recycled easily; if disposed of in landfill, they biodegrade quickly.
Waste water
contains a very lagre maount of organic molecules (from urine and faeces.)
-Alco contains harmful microrganisms like bacteria .
-Sow waste water must be carefully treated beforebeing released back into the environemnet /.
Stage 1 waste water tretment
sweage is screened bby passing htrough a mesh .
-This removes soilds and peieces gf grit .
Stage 2 of wwater treatment
now sewge is allowed to settle in large sedimentation tanks . -This produces liquid effluent and a semi-solid sludge which sinks
-The sludge is takren away and DIGESTED by anaerobic bacteria /
In the abscence of oxygen
These bacteria porduce bio gas which can bebruned for electricity .
-At the end the digestive sludge can bwe used as fertilisers for farms .
Liquid effluent
Contains a large amount of organic molecules and harmful microrganisms , both of these neds to be reduced before the water is returned to the enviornemnt .
-SO air is bubbled htorugh the liquid effulenut allowing aerbic bacteria to multiply .
-IN THE PRESENC EOF OXYGEN AERBOIC BACTERIA DIGEST THE ORGANIC AND HARMFUL MOLECULES AND MICOROEGANISMS .
lAST STAGE OF WATER TREATMENT WASTE
After thsi stgae the liudi effluenet is sfely dischagrched into rivers and deas .
-Alot of the water is used by indusryr likw making paper and hcemicals .
-When this water is treated ny harmful chemicals first need to be removed .
after this stage water can safelygeneral sewage
around the world
treated sewage can be use to make potable watwer .
HOWEVER it takes amny purificatin steps so only done where water is scarce.
around the world
treated sewage can be use to make potable watwer .
HOWEVER it takes amny purificatin steps so only done where water is scarce.
aquifiers
is the easiest way o porduce potbale water , this is water is safe to drinka nd it hs been treted with chlorine .
HOEVER - awuifers cna be polluted (fertilisers from farms) so water from aquifers has to be treated safely /
salt water
need to be desalinated to produce potable watwr .
-However that costs lots of energya nd is expwnive ./
salt water
need to be desalinated to produce potable watwr .
-However that costs lots of energya nd is expwnive ./
salt water
need to be desalinated to produce potable watwr .
-However that costs lots of energya nd is expwnive ./
salt water
need to be desalinated to produce potable watwr .
-However that costs lots of energya nd is expwnive ./
